[填空题]
A 1200-kg car rolling on a horizontalzgl qil3(qfy*6hrz;+ng /x *z surface has speed v = 65 km/h when ksjwg)q1k0ar.a *zt53ud q,g it strikes a horizontal coiled spring and is brought to rest in a distance of 2.2 m. What is thr.st1wuk) 0 d*gaqj,gk a3 z5qe spring stiffness constant of the spring? N/m
